INTERMITTENT ENTERAL FEEDING IN MECHANICALLY VENTILATED PATIENTS - THE EFFECT ON GASTRIC PH AND GASTRIC CULTURES

Objective: To evaluate the effect of intermittent (16 h/d) enteral fee ding (IEF) on gastric pH and gastric microbial growth in mechanically ventilated patients. Design: Prospective, case-controlled study. Setti ng: Medical ICU and infectious disease research laboratory in a univer sity hospital. Patient population: Thirteen mechanically ventilated pa tients receiving continuous enteral feeding (CEF). Methods: Gastric pH and quantitative gastric cultures were obtained while patients receiv ed CEF. Each patient's feeding schedule was changed to IEF. Daily gast ric pH and quantitative gastric cultures were obtained for 5 consecuti ve days. Results: Gastric microbial growth was found in 85% (11/13) of patients receiving CEF, Implementation of IEF did not clear gastric m icrobial growth, as only one patient subsequently reverted to negative culture. Similar gastric microbial growth continued in 90% (10/11) of patients after institution of IEF, Gastric pH did not decrease with t he administration of IEF (gastric pH with IEF, 3.8+/-0.6 vs 4.7+/-0.5 with CEF (not significant [NS]). The amount of microbial growth was al so unchanged with IEF (total growth with IEF, 7.8x10(5)+/-5.2x10(5) cf u/mL vs 8.7x10(5)+/-4.6x10(5) cfu/mL with CEF) (NS). Thirty-eight perc ent (5/13) of patients developed new Gram-negative rod growth in gastr ic cultures while receiving IEF. Gram-negative rod isolates increased from 25% of total isolates (CEF) to 40% (IEF). Conclusion: Our prelimi nary data suggest gastric pH was not lowered and existing microbial gr owth was not cleared in ventilated patients receiving IEF after previo usly receiving CEF, Further controlled study in a larger group of pati ents is necessary to determine whether IEF is of benefit in decreasing gastric colonization and nosocomial pneunonia.